1. Field of the Invention
The present invention relates to mechanisms for operating high voltage switches, and more particularly, to a spiral spring operated mechanism which may be charged either manually or electrically and which may be operated or controlled either manually or electrically to perform both opening and closing switch operations.
2. Description of the Prior Art
The present invention constitutes an improvement over the construction disclosed in U.S. Pat. No. 3,980,977-Evans, entitled "SPIRAL OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH," issued on Sept. 14, 1976, and assigned to the same assignee as the present invention. That patent discloses a spiral spring operating mechanism that can be recharged either manually or by motor and which can be controlled or operated either manually or electrically to both open and close high voltage switches. However, the mechanism disclosed in Evans has the disadvantage of requiring a clutch mechanism to disengage the motor while the spiral spring is being recharged manually. The present invention eliminates the necessity for such a clutch mechanism.
Another disadvantage of the mechanism disclosed in Evans is that it required a significant amount of torque to recharge the spiral spring. The present invention overcomes this disadvantage by providing a gearbox assembly to reduce the torque required to recharge the spiral spring. The lower torque requirement allows a smaller electric motor to be used for recharging the spiral spring, facilitates manual recharging, and lessens the mechanical stress exerted on members of the operating mechanism during recharging.
Additionally, it is desirable to avoid inadvertent tripping of the operating mechanism while the spiral spring is being recharged because such an inadvertent tripping would result in incomplete operation of the associated high voltage switch or its operation at too slow a speed. Such improper operation could cause a failure of the high voltage switch to properly interrupt the circuit or a failure to properly close the switch in the event a short circuit exists on the circuit being energized. Although the mechanism disclosed in Evans provides a shutter bolt that prevents tripping either electrically or manually during manual recharging, the Evans mechanism did not provide a means to prevent tripping while the device is being charged electrically. The present invention, however, provides means for preventing both electric and manual tripping not only during manual recharging, but also while the mechanism is being charged electrically through the motor.
Finally, the switch operating mechanism disclosed in Evans required a separate trip handle to control tripping to close and tripping to open the associated high voltage switch.
Thus, the prior art switch operating mechanism disclosed in Evans does not provide a gearbox assembly to reduce the torque required to recharge the spiral spring. Further, the prior art mechanism does not provide a simple means for releasing the output lever by pivoting a single trip handle right or left to open or close the associated high voltage switch. In addition, in Evans a clutch mechanism was required to disconnect the motor from the mechanism during manual recharging of the spiral spring. Finally, Evans does not disclose a means for preventing automatic tripping while the mechanism is being recharged by the motor.